Centralized traffic controlling system for railroads having track obstruction detecting means



' 2,635,182 CONTROLLING SYSTEM FOR RAILRo oBsTRuCTIoN DETECTING MEANSADS Apnl 14, 1953 T. J. JUDGE :ENTrgM-.Iz-r3w TRAFFIC HAVING 'TRACKFiled March 19, 1946 13 She'ets-Sheet I April 14, 1953 T. J. JUDGE2,635,182

CENTRALIZED TRAFFIC coNTRoLLING SYSTEM ma RAILRoADs RucTIoN DETECTIN@MEANS HAVING TRACK OBST Filed March 19, 1946 13 Sheets-Sheet 2 mz3 E316:@ t2@ u E@ Trn n E262@ mg.- n md Low vwo Eopcs 25 Ssn .SSH 252.6rus.

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ZSnventor April 14,119'53 T. J. .JUDGE 2,6%82 CENTRALIZED TRAFFICCONTROLLING SYSTEM ROR RAILROADS .OBSTRUCTIONYDETEGTING MEANS:

HAVING- TRACK March' 19, 1946.,..5v

Filed 13 Sheetsfsheet 3 1 FIG.. 2B.

Apnl 14, 1953 T. J. JUDGE v 2,635,182

CENTRALIZED TRAFFIC ,CONTROLLING *SYSTEM FOR -RAILROADS HAVING TRACKOBSTRUCTION DETECTINGMEANS Filed March 19, 1946 y 13 Sheets-Sheet 4 s@2g '-12 .g'n g I TUO-11T '-QioA pl'nl 14, 1953 T J, JUDGE 2,635,182

CIINTRLIZED TRAFFIC CONTROLLINGSYSTEM EOE RAILROADS A v HAVING TRACKOBSTRUCTION DETECTING vMEANS Filed March 19, 1946 15 Sheets-Sheet 5 T.J. JUDGE CONT 2,635 ADS April 14, 1953 CENTRALIZED TRAFFIC ROLLINGSYSTEM FOR RAILRO HAVING TRACK OBSTRUCTION DETECTING MEANS Filed March19, 1946 15 Sheets-Sheet 6 WIIL 5N se@ BN. GJM

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ATTORNEY www www NNN A T. J. JUDGE.. 2,635,182 CENTRALIZED TRAFFICcoNTRoLLrNG SYSTEM FOR RAILRoAns April 14, 1953 HAVING TRACK DESTRUCTIONDETECTING MEANS Filed March 19, 1946 13 Sheets-Sheet '7 INVEN TOR. i

ADS

INVENTOR.

ROLLING SYSTEM FOR RAILRO RUCTION DETECTING MEANS 13 Sheets-Sheet 8 if;Ihm Ll A. ,W

T. J. JUDGE CENTRALIZED TRAFFIC CONT HAVING TRACK OBST ffl-1 @VT i l I lI V @4S i 515 Z 7%/ ATTORNEY April 14, 1953 Filed MaICh 19p 1946 FIG..3B.

April 14, 1953 T. J. JUDGE 2,635,182

CENTRALIZED TRAFFIC coNTRoLLlNG SYSTEM-FOR RAILgQDs HAVING TRACKOBSTRUCTION DETETING MEANS Filed ,March 19, 194e 1 3; sheets-sheet 9 FP1H 4 18al- 4 P -v' m21 l 12545 L.: 1 :1&2 1 CP .l 181 April 14, 1953 T J,JUDGE 2,635,182

CENTRALIZED TRAFFIC CONTROLLING SYSTEM FOR RAILROADS HAVING TRACKOBSTRUCTION DETECTING MEANS Flled March 19, 1946 13 Sheets-Sheet l0FIG.. 3D.

17 l :176 lF- H l u I ATTORN EY 2,635,182 ADS April 14, 1953 T. J. JUDGECENTRALIZEU TRAFFIC CONTROLLING SYSTEM Foa RAlLRo NG MEANS HAVING TRACKFiled March 19, 1946 OBSTRUCTION DETEGTI 143 sheetslsheet 11 ZLENTOR.

Fllea March 19 1946 T. J. JUDGE 2,635,182

CENTRALIZED TRAFFIC CONTROLLING SYSTEM lFOR RA-ILROADS HAVING TRACKDESTRUCTION DETECTING MEANS 15 Sheets-Sheet 12 ZELT:

INC'R Suvemtor Plll 14, 1953 A T. J. JUDGE 2,635,182

y CENTRALIZED TRAFFIC CONTROLLING SYSTEMKEOR RAILROADS l HAVING TRACKOBSTRUCTION DETECTING MEANS Filed March 19, 1946 -15 Sheets-Sheet 15 INV EN TOR.

au ATTORNEY Patented Api'. 14, `1953 2,635,182 CENTRALIZED TRAFFICcoNTRoLLlNG sys- TEM FOR RAILROADS HAVING TRACK OBSTRUCTION DETECTIN GMEANS Thomas J. Judge, Rochester, N. Y., assigner to General RailwaySignal Company, Rochester,

Application March 19, 1946, Serial No. 655,622

This invention relates to centralized traiic controlling systems forrailroads, and it more particularly pertains to a centralized traiccontrolling system employing coded track circuits for controlling thesignals in accordance with railway trailic conditions.

In a centralized trafc controlling system for single track railroads inwhich coded track circuits are employed for the portion of the controlof the wayside signals in the field which is automatic, a problem isencountered to provide coordination between the direction of trafticdesignated by a dispatcher in a control oce and the direction of trackcircuit code transmission through the track rails for the control ofsignals over a corresponding stretch of track. A means for providingsuch coordination is shown, for example, in my prior Patent No.2,357,518, and inanother prior Patent No. 2,357,519, both patents beingdated September 5, 1944. This invention is to be considered as animprovement over the systems disclosed in such patents.

In systems of this particular character, switch and signal control codesare transmitted by a selector system from the central control oflice tothe signal locations at the respective ends of the passingvsidings inaccordance with switch and signal operational designations by adispatcher in the usual manner, and the designation by a dispatcher of asignal desired to be cleared is effective automatically to cause thetransmission to the next iield station in advance of that signal of acode to render effective the transmission of track circuit codes asrequired for the control of that signal and the intervening automaticsignals between that signal and the next centralized traffic controlledsignal location in advance.

An object of the present invention is to provide a centralized tratliccontrolling system havingcoded track circuits in which the codetransmitters for transmitting the track `circuit code pulses arenormally inactive, but such code transmitters can be rendered active inresponse to the respective designation at the control cnice of thesigna-ls desired to be cleared. The transmission of track circuit codesthus established is maintained active for a particular direction of codetransmission until 4automatically rendered inactive after passage of atrain, or after the established route has been restored by actonof thedispatcher at the control cnice. It will be readi-ly apparent that if adispatcher could transmit a control from the control office that wouldcall IOra direction of traine contrary to that estab- 6 Claims. (Cl.246-121) lished through a, stretch of track occupiedby a train betweenpassing sidings, the track circuit code upon which the train isdependent could be taken away, and thus cause delay because of removalof track circuit code requiredfor clearing the intermediate signalsbetween passing sidings.

Another object of the presentA invention is therefore to provide aninterlocking means at the control of'lce for permitting the transmissionof signal control codes for the establishment of traic in a directionopposite to the direction last established in a stretch of single trackonly subsequent to the reception of an indication at the control ocecommunicated from the eld that such stretch of track is unoccupied by atrain.

Another object of the present invention is to indicate over the trackrails and by code communication to the control oflice dangerous con`ditions along the trackway such as land slides, washed out bridges, andthe like at any time that such conditions may occur even though thecoded track circuit apparatus may be normally inactive at that time.

Another object of the present invention is to provide adequate means forgoverning an electric lock associated with an outlying track .switch ina stretch of track between passing sid-Y ings so as to allow the releaseof such lock for the passage of a train out of the outling switch,v

dependent upon a required act of the dispatcher at the control ofce, anddependent upon a check of occupancy of the particular block with whichsuch outlying track switch is associated, such control beingaccomplished by the use of `coded track circuits with their codetransmitters controlled at the ends of the block by the centralizedtraic controlling communication system associated with such ends. l l

Other objects, purposes and characteristic features of the presentinvention Will be in part obvious from the accompanying drawings and inpart pointed out as the description of the invention progresses.

In describing the invention in detail, reference will be made to theaccompanying drawings inV which those parts having similar features andfunctions are designated throughout the several illustrations by likeletter reference characters which are generally made distinctive byreason of preceding numerals indicative of the location oi the signalsor track switch with which such parts are associated, and in which- 1Figs. 1A and 1B, when placed end to end v,re-1

apparatus and circuit organizational: the control oflice required forthe operation of Vthe system provided by the present invention;

Figs. 3A, 3B, 3C, 3D and 3E, when placed side by side respectively,illustrate the stretch of trackway between two passing sidings for thisembodiment of the present invention together with coded track circuitmeans for controlling-the switchesV and signals, and under certainconditions Fig'sii will be considered as being placed at the right ofFig, `3E to show a stretch of main track withits associated passingsiding; n l

Fig.`4 shows certain circuits typical to the centralized ltrafliocontrol of switches .and signals at al given field station;

Figj illustrates a typical manner of controlling application relays at agiven field station in accordance with code impulses communicated by thecommunicationsystem to that iield station; and

Fig. 6 shows a code chart indicating how various control codesareassigned to the respective channels of a control-cycle.

The illustrations employed in the disclosure of this` embodiment of thepresent invention have beenvarranged tov facilitate the disclosure ofthe invention as to the mode of operation and the principles involvedrather than for the purpose of illustrating the construction andarrangement of parts that would be employed-in practice. Thus the relaysand the contacts are shown in a conventional manner, certain relaycontacts being shown in written circuit form and identified as ofparticular relays b y corresponding reference characters appearing abovesuch contacts,

The symbols (-1-) and are employed to indicate the. positive andnegative terminals respectively of suitable batteries .or other sourcesvofi d' ect current and the .circuits with which these symbols. 'are usedalways. have current `flowing in the same, direction.. The. symbolsy(B+) and (l-l are used to indicate. the respective positive and negativeterminals of. e center tap battery or other suitable.. soureeoi directcurrent. and. the center tap of; such source isindicated by the symbol(CN.)- .The symbol (FLM is usedto indicate connection to the. positiveterminal of a suitable, source of direct current through'a suitableinter. mittently actuated contact to provide intermittent energization.The Symbols (LS) and (SL) are used to indicate code characterstransmittedover the. communication systemeacb character ccmpri'sing-acombination of along and short period, the. symbol (LS) representing acode character having long and short periods respectively, and thesymbol (SL) representing a, code character having short and long periodsrespectively.

In order to simplify the description of the prese entinventionreferenceis made from time to time.

to. 'functions .common to all parts ci a similar nature :by use in thedescription of letter reference characters common to .such parts withouttheir preceding numerals and/or exponents. it is to be understoodthatsuch a reference applies to any parts-designated in thedrawings byreference characters that are similar except for exponents or precedingnumerals associated therewith.

The trackway for which this embodiment of the present invention isprovided, comprises a main stretch of track having passing sidingsassociated therewith, suchrstretch of track .being divided into theusual track sections to provide several track sections constituting ablock between passing sidings. With reference to Fig. 3A, a passingsiding is illustrated as being connected at its right-hand end to themain track by the track switch IW, and

' similarly in Fig, 3E, the left-hand end of a passing siding isillustrated as being connected to the main track by a track switch 3W.An outlying switch 2W isshown in Fig. 3C as being connected to the maintrack.and it is to be understood that .such track switch is provided forhand-throw operation in the usual manner with the hand operation ofthetrack switch limited by the usual type of an electric lock. it will bereadily apparent as the description progresses. that .the track switch`2W yand the control apparatusiassociated with the main tracklasillustrated `in Fig'. 3Ccan be provided when required in practice, but.the system is operative without the apparatus dis-` closed in Fig. 3Cunder conditions wheresuch outlyingswitch is not required in practice.

rIihe arrangement of the signals at the `ends oli the passing sidings isprovided in the usualmanner to provide a short detector or OSgtraQksection for the track switch at each end of the passing siding. Thedetector track section :2-3T'is provided for the right-hand end .ofthepassingr siding illustrated in Fig. 3A, for example. Such detector tracksection has a steadily energized track .circuit provided in thev usualmanner. The poweroperation of the track switches at the respective endsof the passing sidings can be. provided. `for example, by a suitablepower switch machineecon,- trolled as shown in `Fig. 4 Y

The signals at the respective. ends ofr thepass-` ing sidings areprovided forgoverning traiczin each direction kover the kdetector tracksection "at such passing siding suchsignals being normally at,v stop,and subject to manual control by an opera-,- tor at the control Officein .accordance with .the communication ofcontrolsfor suc'hsignals torespective vfield stations by a code communication system such asdisclosed indetail, for exampla'in the prior application of Hailes, etal.,'Ser. No 48,4328, dated April 27:, 1943 which has resulted in Pat.No.` 2,399,734, dated May '7., 1,946..

Although this embodiment .of the presentinvention has beeninarticularlyadapted tocmpioyf the centralized traiic .controlling code.communication system disclosed in Vthe, above mentioned' Haleset al.application, it is to .be understood that other types of codecommunicationsystems could be readily employed by those skilled in theart, such, for examplaas the codecommunication system disclosed in thepatent to. Judge, etaLrNo, 2,682,544, dated June, 1,1937. i lTheentering signals `3A and 3B. at the right-. hand end or the passingsidingillustrated in Eig..v 3A are provided for governing westboundtralc over the track switch lW through thetrack-seotion 2 3'1, and thehead-block signals 2A .and

2B are .provided forgoverning eastbound traffic through that tracksection. At the left-lhand'end of the passing siding illustrated inFig'. 3E, the signals 8A and 8B are provided for governing eastboundtraffic through the OS track section 8-9T and/the signals @A and'eB areprouidedfor con-V trolling westbound traino through such section.

Intermediate signals, which are controlled only in ,accordance withcoded track circuits transmitted through the track rails of therespective track sections of the block illustrated between passingsidings, areiprovided at double intermediate signal locations, but itwill be readily apparent as the description progresses that the presentarrangement can be modiiled to provide control for staggered automaticsignal locations in accordance with the requirements of practice. Theintermediate signals 4 and i3 are automatic signals provided forgoverning eastbound traffic in the block between the passing sidingsillustrated, and the signals 5 and l are provided for governingwestbound traffic in such block.

Although the. signals illustrated are of the searchlight type, it is tobe understood that other types of signals such as the color light typehaving individual color lamp units, semaphore, or position light signalscould as well be employed.

Each of the track sections in the stretch of track between the passingsidings, except for the short release track section RT associated withthe outlying track switch 2W, has a coded track circuit which comprisesa track battery and a codeV following track relay TR at each end of thetrack section. For the purpose of obtaining the best operatingconditions of the code following track relays, it is desired that eachrelay havea polar structure so arranged as to cause the relay contactsto be biased to a deenergized position from which they can be moved uponenergization of the relay windings with a particular polarity only. Alsoassociated with severalof the coded track circuits is a series approachcontrol relay AR which can be 0i a similar character to the trackrelays, and certain of the approach relays AR have slow acting repeaterrelays ARS associated therewith.

At the ends of each of the track sections having a coded track circuit,is a code transmitter relay CP or CPR, which is operated when renderedactive to apply a code of pulses at that end of the track circuit at aselected rate. For the purpose of obtaining the most desired operatingcharacteristics of each of the relays CP, such relay is also providedwith a polar structure to provide the operating characteristics abovedescribed as being preferable for the code following relay TR.

Relays TP and FP at eachend of each coded trackcircuit are provided asfront contact repeaters of the track relay TR at such end, the relay TPbeing quick acting to follow the codes received, while the relay FP ismade to be sunlciently slow acting as to be maintained picked upwhenever a code of either of the code rates employed is received. Alsoat certain switch or signal locations a slow acting back contactrepeater relay BP is provided that is energized through a back contactof the associated track relay TR, provided that the associated frontAcontact repeater relay FP is picked up.

East and west directional stick relays S are 6; maintained steadilypicked 'up during the'time when a track circuit code is beingreceived.Each of the relays D is energized through the medium of a decodingtransformer and a tuned circuit in a manner generally employed in codedtrack circuits so as to cause such relay to bepicked up only in responseto a particular code rate employed for the `clearing of signals. In thisembodiment of the present invention the code rate for energizing therelays D is attimes a 120 rate and at other times a 180 rate. At theends of the block, relays DX are providedso as to be tuned to a 180rate, and the purpose of such relays is to provide by their response anindication that the entire block is unoccupied by a train.

Suitable code forming means ls provided at the respective signallocations such, for example.'

as code oscillators or motor driven coders to form the different coderates employed. For this embodiment of the present invention, anoscillator ICT is provided for each of the signal locations for forminga 180 code, an oscillator IZUCT is provided at each of the intermediatesignal locations for forming a code, and an oscillator 15CT is providedat each of the signal locations for forming a 75 code.` o

Each of the field stations has olilce controlled application relays asshown in Figs. 1A and 1B, the relays LGZ and RGZ being provided forgoverning the signals for westbound and eastbound directions of traicrespectively, and a relay B being provided at each of the field stationsfor useV in the manual restoration to stop of signals by the dispatcherat the controlofllce.' Relays WN and WR are provided at each of thefield stations for causing the power operation of the switch machine SMat such stationto its respective normal and reverse positions.

The initiation of the track circuit code transmitter relays CP for theends of the coded track sections adjacent the respective iield` stationsis provided at each station in accordance with the control from thecontrol oflice of eastbound and westbound traine direction relays RFZand LFZ respectively. These relays are of the magnetic picked up ordropped away position as last voperated over the code communicationsystem from the control office.

At the control olice (see Figs. 2A to 2C inelusive) various switch andsignal control levers, and relays are provided for purposes specificallyset forth in the above mentioned application of Halles, et al., Ser. No.484,728, filed April 27, 1943, which has resulted in Pat. No. 2,399,734,

dated May 7, 1946, to which reference is to be v made for a descriptionin detail of such apparatus. For convenience in readily identifying theapparatus employed in this embodiment of the present invention with thatshown in the above mentioned Halles, et al. application, correspondingletter reference characters for the various relays and control switcheshave been employed to facilitate the reference to such application Vfora more detailed description of their mode of operation. Thiscommunication system includes relays SA, LV, B, and CS. The relay SA issteadily picked up Vduring a cycle of operation; relay LV is picked upat the end of a cycle; relay B is a lsignal stop control relay; andrelays CS are decoding relays.

In addition to the relays generally employed.

in the code communication system, the present 7 lnveirectingautomaticstarts of the system for the Vtransmission of control Vcycles ofoperation used in transmitting controls for the initiation of the trackcircuit code transmitters vat the respective iield stations. Associatedwith the relays ACH is a repeater relay ACI-IP which is picked up eachtime an `automatic start is initiated forthe transmission'of a controlcycle of operation for the 'starting of any particular track circuitcode transmitter. The function of such relay A'CHP Awill be moreapparent as the description progresses, 'it generally being `e`mployedto render the transmission oi a 'control cycle for the starting orshutting :down of a track circuit code `transmitter ineffective `forcontrolling signals at that particular eld station. A

The code communication system also includes codefdetermining rela-ys forlselecting respective codes V-for transmission 'to therespectivestations, fand a stick relay LCS, the principal function ofwhich is to prevent thechanging of the condition of the relays LC during'a communication cycle.

The relays RFS and LFS are provided for each block and for each sidingsection for maintaining an interlock -in the traiiic direction set upwithin such track portion. 'That'is the purpose of such relays is -toprevent the transmission of control `codes to the eld for changing 'thedirection of `code transmission in the coded 'track circuits, providedsuch controlsY should be inadvertently designated for transmission by anoperator `of thecontrol machine. It is therefore provided that therelays RFS and LFS are controlled in accordance with conditions ofytrack circuit code transmission in the iield, indication of Suchconditions being communicated to the omce to condition the indicationresponsive relays at the cnice such as the relays WK, GK, TK and BK.Relays of this type are magnetic stick relays so as to be maintained intheir picked up or dropped away respective positions in accordance withthe particular `character of energization last applied to such relays.Relays 2WL and ZWLS are provided at the control oiilce as part of theapparatus governing the transmission of controls for a Switch lock inthe eld.

Having thus considered the general organizationof the apparatus employedin this embodiment of the present invention it is believed that thespecific circuit organization can best be understood when consideredv inconnection with specific typical conditions of operation of the system;Y

Operation Gcneral.-Beiore considering Aspecifically the circuitorganization provided for establishing various routesthrough the tracklayout, some consideration will be given. as to the. generalmode ofVoperation of the system without attempting to ydescribe specificallythe circuits employed to accomplish such operation.

In accordance with the general manipulation of the control machineaccording tothe usual practice, the machine .operator positions therespective switch and signal control levers according to routes desiredto be established, and effects the transmission of controls to .therespective eld stations with which such levers are associated by theactuation of start buttons associated with such field stations. In thismanner a number of different controls can be designated fortransmission, and the circuit organization Vof the code communicationapparatus is such as to cause the transmission of control cycles tosuchneld stations, one cycle of 'operation at a time and one cycle 'ofoperation for each station, such cycles being transmitted in aparticular predetermined order, and such order being established by thecircuit organization for the relay LCS in which the relays LC have theirrespective contacts inserted in series in the circuit for the relay LCS.

Thus the designation of the controls for transmission to a field stationby the positioning of switch and signal control levers SW and SIG, 'anothe actuation of the start vbutton for causing the transmission of thesecontrols, is eiiectve to first pick up the relay C-I associated with theinitiation of the control cycle start for that eld Station, and thepicking up of such relay is effective to 'pick up the associated relayLC. The picking up of the vrelay LC for that neld station is accordancewith the actualsetting into operation oi the code communicationsystemior .the trans-fy mission of the control cycle to that parti-culareld station, and in accordance with the picking up of such LC relay, acircuit is closed 'to Acause the picking up ofthe :relay ACHassociatedwith the nexteld station in advance of the signal desired tobe cleared for causing an automatic start for the transmission ofcontrols to that eld sta-i tion. Thus, in general terms, the initiationof the system for the .transmission of a controlfor clearing a signal,is eiiectiv'e to Ypick up a relay AC1-I for the next field station `inadvance of the signal desired to be cleared Vtoftlfiereby cause .theinitiation of a subsequent cycleof operation for the transmission of aAcontrol/to the next eld station in advance to start vthe vtransmission.`ot track circuit codes through the track rails in. the direction of thesignal desired to be cleared.

As soon as the `track circuit code `has been transmitted throughthetr'ack rails to the signal desired to be cleared, a relay FP ispicked up-in the field, andthe picking up of such relay is effective totransmit an indication to the control oin'ce that the code transmittershave been properly" conditioned in accordance with the routedesired toce established. Upon the reception at the control ofIlce of suchindication, the-relays LFS-.andi RFS for the particular stretch of trackbetween eld stations involved are conditioned to estab--vv lish aninterlock and prevent the 'inadvertent removal of the track circuitcodes thus estab#v lished, as by an inadvertent attempt Vat transmissionof the controls from the vcontrol vofdcenfor a direction of trainocontrary to that already established through thatl particular stretchof' track. Having therefore established a-route for aV train in thefield, and having established an interlock in the control ofice `toprevent the taking. away of that route or any portion thereof, it will'be assumed that the passage of a train is effective" in the eld oversuch route, and subsequent to 'the' passage of such train, an indicationkis trans mitted to the cnice that the particularV stretch of trackinvolved is unoccupied, and in accordance With the reception o `suchindication, a relay ACH control olce to that iield station under such-1conditions isl such kas to cause the dropping away of a relay FZ at thateld station to render the` track circuit code transmittery `inactive/atthat station and therefore restore the conditions te normal for thestretch of track under consideration above. l

Normal conditions-Normally, with no routes established, and with thetrackway unoccupied by trains, the transmitters and receivers of trackcircuit codes are inactive, and therefore the wayside signals are atstop, and the only relays that are energized under such conditions arethe track relays TR that are controlled by steadily energized trackcircuits, and such other redays as are provided for repeating normalconditions of the system.

The slide detector relays SD (see Figs. 3A and 3E) at the respectiveends of the block between passing sidings are normally energizedso as toprovide a means responsive to a condition of slide detection which maybe desired to be established at a time when the system is normallyinactive or at rest. The slide detector relay ZSD, for example, ismaintained picked up under normal conditions by the energization of anobvious circuit closed at back contact 20 of relay EFP.

,a The approach locking relays AS (see Fig. 4) are normally energized bycircuits provided in accordance with the usual practice for the controlof time or approach release locking. `The relay 2AS,` for example, isnormally energized by a circuit extending from (-1-), including frontcontact 2| of relay ZRP, front contact 22 of relay 2AS, and winding ofrelay 2AS to It will be noted that energy for this circuit is appliedthrough front contact 2I of relay ZRP, such relay being normallyenergized in accordance with the signals 2A and 2B being at stop by acircuit extend-` ingfrom (-1-), including normally closed contacts 23and '24 of signal 2B and contacts 25 and 26 of signal` 2A, and windingof relay ZRP, to The normal correspondence relay INCR for the trackswitch IW is normally energized in accordance with the closure of acircuit extending from (-1-), including front contact 21 of relay IWP,polar contact 28 of relay IWP in its righthand position, front contact29 of relay I WN, and winding of relay INCR, to The lock relay IL forthe track switch IW is energized normally by a circuit extending from(-1-), including front contact 30 of relay 2-3TR, back contact 3I ofrelay A-LGZ, back contact 32 of relay A-RGZ, front contact 33 of relay3AS, front contact 34 of relay ZAS, back contact 35 of the thermal relayTE, and winding of relay IL, to The relays IL and ILS are used inproviding for the safe operation of the track switch IW in a well knownmanner generally employed in practice.

The magnetic stick relays, under normal conditions when` the system isat rest, of course assume their last operated positions, and it is to beconsidered that the last conditions established as by the passage of atrain and the restoration of all the switch and signal control levers totheir center positions has provided that the magnetic stock relays havebeen operated to their dropped-away position as indiacted in thedrawings.

Transmission of controls at the control cinica- With reference to Fig.6, a code chart is shown showing the manner in which a control cycle ofoperation comprises all of the switch and signal and trainedirectionycontrol codes required for transmission to any particular eldstation. It will be noted that the composition of the cycle is such asto allocate the rst group of pulses for control station selection, thenext pulse for. switch-control, the next fololwing pulse for the`rendering active or inactive of a track circuit code transmitter inconnection with the transmis-vv sion of track circuit codes through thetrack rails to the left of that field station, the next follow-` ingpulse for therendering active or inactive 0f a code transmitter inconnection with the transmission of track circuit codes through thetrack' rails to the right of that eld station, and the last two pulsesfcrthe control of the signals at that field station.` It will be notedthat the signal control code characters(LS) for both of the signal codepulses is an additional code to that usually provided for the control ofthe signals, and

such code `is merely used as a phantom code dur-fing the transmission ofa cycle of operation which has been automatically initiated. It will beread' ily apparent that it is desirable under such conditions ofautomatic initiation of transmission to leave the control of the signalsas last established by the dispatcher.

To consider further the manner of transmission of control -cycles ofoperation for the establishment of routes, it will be assumed, for thepurpose of illustration, that it is desired to establish` with suchcontrol levers to initiate the cycle of operation.

In accordance with theclosure of the start button contact 36, an obviouscircuit is closed to pick up relay A-CI-I, and a stick circuit is es`tablished to maintain such relay picked up until a control cycle hasbeen initiated, extending from (-1-) including back contact 31 of relayA-LC, front contact 38 of relay A--Cl-I, winding of relay A-CI-I, andnormally closed contactl` of the cancel button CAN, to

Upon the picking up of relay A-CH a circuit is closed to cause thepicking up of relay AA-LC extending from (-1-), including back contact40 of relay SC, back contact 4I of relay C, back contact 42 of relayLCS, front contact 43 of relay A--CH, lower winding of relay A-LC, frontcontact All of relay A--CH, and normally closed contact 39 of the cancelbutton CAN, to

The relayLCS is picked up to further initiate the starting of a controlcycle, in accordance withv the picking up of relay A--LC, by theenergization of a circuit extending from (-1-), including back contacts45, it and 4l of relays C, SC and LV (see Fig. 2C) respectivelyconnected in multiple, winding of relay LCS, front contact 48 of relayA-LC, upper winding of relay A-LC, and the normally closed contact 39 ofthe cancel button CAN, to Upon the picking up of relay LCS by theenergization of the circuit just described, a circuit (not shown) isclosed to cause the picking up of the relay C for starting thecommunication of the control cycle. The manner in which the relay C iscontrolled to provide such mode-of operation, and the manner in whichthe relay LCS is maintained energized throughout the control cycle,isfully described inthe above mentioned application of Hailes, et al.,Ser. No. 484,728, dated April 27, 1943.

Assuming the `control cycle to be starte-d, the stepping relays V (seeFig. 2C) are picked up in order according to the numerical order definedby their numerical reference characters, the first 13 relay ACHP, suchrelay ACHP being common to the automatic starts for all eld stations andhaving a purpose to be hereinafter described. In accordance with thepicking up of the relay BLC, under the above described conditions, therelay LCS is picked up, upon the establishment of the stick circuitforrelay B-LC, by the energizationcf a circuit extending from includingback contacts 4l, 4B and S5 of relays LV,

SC and C respectively, connected in multiple, Winding of relay LCS,front contact 1l of relay B-LC, upper winding of relay B-LC, and no1'-mally closed contact 39 of the cancel button CAN to It will be notedthat a stick circuit is also closed t maintain the relay ACHP picked upthroughout the control cycle by the energization of a circuit extendingfrom including back contacts 4l, 46 and 45 of relays LV, SC and Crespectively, connected in multiple, front contact 18 of relay ACHP,upper Winding of relay ACHP, and normally closed contact 39 of thecancel button CAN, to

y In accordance with the picking up of relay B-LC, the stati-on code forselecting field station B is transmitted, and subsequent to thetransmission of that code, the relay LS is picked up for thetransmission ofa switch control character in accordance with the normalposition of the switch control lever SSW ina manner similar to thatdescribed above for the transmission of a similar character inaccordance with the normal position of the switch control lever HSW.

The code character following theV switch control character will berequired to be the character (LS) in order to cause the picking up ofthe relay B-RFZ (see Fig. 3E) at field station B, thus the relayl LS isenergized upon application of energy to the channel wire 5B by a circuitextending from such channel wire 5) including, front contact 19 of relayB-LC, back contact 80 of relay SLFS, back contact 8i of relay 2RFS, backconta-ct 82 of relay A-ACH, contact 63 of signal control lever 2-3SIG inits right-hand position, and winding of relay LS, to

The following character of the code, for governing the track circuitcode transmitter at the right of the eld station B, will be an (SL)character because it is not desired to start the transmission of drivencodes in the coded track circuit 8-I IT at the end adjacent fieldstation B. The energization of relay SL for such character is effectiveupon the lapplication of energy to the channel wire 5l by the closure ofa circuit extending frcm such channel wire 5l, including front contact83 of relay B--LC, wire 34, back contact 85 of relay BRFS, back contactBt of relay |\|LFS,`back conta-ct 8l ofrelay C-ACH, contact 88of theswitch control lever 4SW in its right-hand position, contact B9 ofsignal control lever Ill-l SIG in its centerposition, Awire 9G, andwinding of relay SL, to

Inasmuch as no controls for the switches and signals in eld station Bhave been designated by the operator, according to the code chart Shownin Fig. 6, the signal control code characters to be transmitted will berespectively both (LS) characters 4so as not toaffect the control of thesignals at field stati-on B. It Will be readily apparent as thedescription 'progresses that the transmission of this code isineffective to control the signals at field station B, even though suchsignals may be clear for one direction of traic or the other.

The relay ACHP (see Fig. 2A) is picked up each time an automatic startis initiated for the transmission of a control cycle to select that thecharacters of the signal control portion of the control cycle are suchas to apply both characters as (LS) characters. This arrangement isprovided as shown in Fig. 2C by the closure of a circuit for the relayLS for the first signal control character extending from including codecommunication contacts (not shown), back contact Si of relay LV, backcontact 92 of relay Vt, front contact 93 of relay V1, front contact Sillof relay ACHP, and winding of relay LS, to It will be noted from thecircuit just described that the closure of 'back contact 94 of relay`ACHP during a control cycle provides a connection to the regular signalcontrol channel' wire 52 for the transmission of all cycles of operationexcept those that are 4automatically initiated.

In a similar manner, the second character of the signal control portionof the control code is selected by the picking up of the relay LS, inaccordance with the picking up of relay V8, 'by the energization of acircuit extending from including code communication contacts (notshown), ba-ck contact 9| of relay LV, front contact 92 of relay V8,front contact 95 of relay ACHP, and winding of relay LS, to It will benoted that the closure of back contact 95 of the relay ACHP appliesenergy to the channel wire 53 in the usual manner for all cycles ofoperation other than those automatically initiated.

Having thus consideredin detail the mode of` operation and specificcircuits involved in transmitting the control codes required for theclearing of a particular signal, it is believed that it will be readilyapparent to those skilled in the art how a similar mode of operation isfollowed in the clearing of other signals as requiredfor the properdispatching of trains through the track layout. Inasmuch as some of theapparatus associated with the transmission of controls tol therespective eld stations is common to both directions of traffic, someconsideration will be given to the clearing of another signal for theopposite direction of traiiic.

It will therefore be assumed, that the route which has been described asdesired to be established from signal 2A to signal 8A is to be used by atrain which will enter the passing siding at field station B for meetinga Westbound train for which a route will be established from signal l IAto signal 9A. In. accordance withthis proposed trarric condition, itwill rst be assumed that an operator operates the signal control lever8-5SIG (see Fig. 2A) to its right-hand position and the switch controllever SSW to its reverse position for causing the clearing of signal 8B.

In accordance with the positioning of these switch and signal controllevers, the subsequent closure of the start button contact 96 causes thepicking up of the relay B-CI-I by the energization of a circuitcorresponding t-o the circuit described by which the relay A--CH iscontrolled.

In accordance with the picking up of the relay B-CI-I, the relay B-LC ispicked up by the energization of a circuit extending from in- Cludingback contact l0 of relay SC, back contact :il of relay C, back contact42 of relay LCS, back contact 33 of relay A-CH, back contact 'H of relayA-ACH, back contact 'l2 of relay B-ACH, front contactii'l of relay B-CH,lower winding of relay B-LC, front contact 'I3 of relay cancel buttonCAN, to Upon the picking

